Hormone releasing IUD increases BC relapse risk

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Hormone-Releasing IUD May Increase Breast Cancer Relapse Risk in Some Patients

NEW YORK AUG 26, 2008 (Reuters Health) - Women who develop breast cancer while using a levonorgestrel-releasing intrauterine device (LNG-IUD) and continue to use it may be at slightly higher risk of breast cancer recurrence following treatment, physicians in Belgium report.

Dr. Xuan Bich Trinh, at St. Augustinus General Hospital in Wilrijk, and colleagues investigated breast cancer recurrence in patients using the LNG-IUD. The researchers note in the July issue of Fertility and Sterility that the device is sometimes used by breast cancer patients, for contraception and to treat heavy menstrual bleeding in women who are premenopausal, and to prevent endometrial changes while on tamoxifen.

However, in vitro studies have suggested that levonorgestrel may stimulate breast cancer cell growth.

Dr. Trinh's group compared 79 breast cancer patients who used the LNG-IUD during a subsequent disease-free period, and 120 patients who never used the LNG-IUD. The groups were closely matched for age at diagnosis, tumor stage and grade, and treatment modalities.

During a mean follow-up of 2.9 years, overall recurrence rates were 21.5% in the LNG-IUD group and 16.6% in the control group, a nonsignificant difference.

However, the 38 patients who were using the LNG-IUD at the time of cancer diagnosis and did not have it removed were at higher risk of recurrence compared with controls (adjusted hazard ratio 3.39, p = 0.048).

Recurrences were metastatic in 100% of women who were using the LNG-IUD at diagnosis, vs 30% of women who received a LNG-IUD after treatment, suggesting that "tumors that develop while being exposed to levonorgestrel are more aggressive."

To validate and to clarify the clinical significance of these findings, Dr. Trinh's group is conducting a more comprehensive, prospective cohort study of premenopausal breast cancer patients in Belgium.

SOURCE:

Fertil Steril 2008;90:17-22.